Time domain coexistence of rf signals

ABSTRACT

Various methods and systems are provided for time domain coexistence of RF signals. In one example, among others, a method includes obtaining access to a WLAN channel during a free period of a coexisting cellular connection, providing a RDG to allow another device to transmit for a duration corresponding to at least a portion of a TXOP, and receiving a transmission during the duration. In another example, a method includes obtaining access to a WLAN channel during a transmission period of a coexisting cellular connection and providing a protection frame to defer transmissions from another device for a duration corresponding to at least a portion of a TXOP. In another example, a method includes determining a shift of a BT transaction based at least in part upon a schedule of cellular communications and shifting at least a portion of the BT transaction based upon the determined shift.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. §119from U.S. Provisional patent application entitled “COEXISTENCE SYSTEMSAND METHODS,” having Ser. No. 61/570,922, filed on Dec. 15, 2011, and isa divisional application of U.S. patent application entitled “THE DOMAINCOEXISTENCE OF RF SIGNALS,” having Ser. No. 13/716,540, filed on Dec.17, 2012, which are incorporated herein by reference in their entirety.

BACKGROUND

Communication systems typically operate in accordance with one or morecommunication standards. Wireless communication systems may operate inaccordance with one or more standards including, but not limited to,Institute of Electrical and Electronics Engineers (IEEE) 802.11, Wi-FiDirect, Bluetooth, advanced mobile phone services (AMPS), digital AMPS,global system for mobile communications (GSM), code division multipleaccess (CDMA), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), and/or variationsthereof. Radio frequency (RF) signals of the wireless communicationsystems are transmitted over a wide range of frequencies. When RFsignals are communicated at frequencies that overlap or are in closeproximity to each other, the RF signals can mutually interfere with eachother resulting in degraded performance. Examples of RF signals that canmutually interfere include, e.g., cellular long term evolution (LTE)signals, wireless local area network (WLAN) signals, Bluetooth (BT)signals, and BT low energy (BTLE) signals.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present disclosure can be better understood withreference to the following drawings. The components in the drawings arenot necessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the present disclosure. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is a graphical representation of an example of a communicationdevice in accordance with various embodiments of the present disclosure.

FIG. 2 is a graphical representation of an example of coexisting radiofrequency (RF) signals of the communication device of FIG. 1 inaccordance with various embodiments of the present disclosure.

FIG. 3 illustrates an example of a predictor map for cellularcommunications of the communication device of FIG. 1 in accordance withvarious embodiments of the present disclosure.

FIG. 4 is an example of a networked environment including acommunication device supporting coexisting Wi-Fi and cellularcommunications in accordance with various embodiments of the presentdisclosure.

FIGS. 5, 6, and 7 are examples of the coordination of coexistent Wi-Fiand cellular communications by the communication device of FIG. 4 inaccordance with various embodiments of the present disclosure.

FIG. 8 is an example of a networked environment including acommunication device supporting coexisting Wi-Fi and cellularcommunications in accordance with various embodiments of the presentdisclosure.

FIGS. 9, 10, 11, and 12 are examples of the coordination of coexistentWi-Fi and cellular communications by the communication device of FIG. 8in accordance with various embodiments of the present disclosure.

FIGS. 13 and 14 are examples of the coordination of coexistent Wi-Fi andcellular communications by the communication device of FIGS. 4 and 8 inaccordance with various embodiments of the present disclosure.

FIGS. 15A and 15B are flowcharts providing examples of coordination ofcoexisting Wi-Fi and cellular communications in accordance with variousembodiments of the present disclosure.

FIG. 16 is an example of a networked environment including acommunication device supporting coexisting Bluetooth and cellularcommunications in accordance with various embodiments of the presentdisclosure.

FIG. 17 is a graphical representation of an example illustrating therelationship between TeSCO and WeSCO in a Bluetooth eSCO pattern inaccordance with various embodiments of the present disclosure.

FIGS. 18A, 18B, 19A, and 19B are examples of the coordination ofcoexistent Bluetooth and cellular communications by the communicationdevice of FIG. 16 in accordance with various embodiments of the presentdisclosure.

FIG. 20 is a graphical representation of Bluetooth clock estimation inaccordance with various embodiments of the present disclosure.

FIGS. 21A and 21B are an example of the coordination of coexistentBluetooth and cellular communications by the communication device ofFIG. 16 in accordance with various embodiments of the presentdisclosure.

FIGS. 22A and 22B are an example of the coordination of coexistentBluetooth low energy and cellular communications by the communicationdevice of FIG. 16 in accordance with various embodiments of the presentdisclosure.

FIG. 23 is a flowchart providing an example of coordination ofcoexisting Bluetooth and cellular communications in accordance withvarious embodiments of the present disclosure.

FIG. 24 is an example of a networked environment including acommunication device supporting coexisting Wi-Fi, Bluetooth and cellularcommunications in accordance with various embodiments of the presentdisclosure.

FIG. 25 is a flowchart providing an example of coordination ofcoexisting Wi-Fi, Bluetooth and cellular communications in accordancewith various embodiments of the present disclosure.

FIG. 26A through 26F are examples of the coordination of coexistentWi-Fi, Bluetooth and cellular communications by the communication deviceof FIG. 24 in accordance with various embodiments of the presentdisclosure.

FIG. 27 is an example of adaptively coordinating coexistent Wi-Fi,Bluetooth and cellular communications by the communication device ofFIG. 24 in accordance with various embodiments of the presentdisclosure.

FIG. 28 is a schematic block diagram illustrating an example of thecommunication device of FIGS. 1, 4, 8, 16, and 24 in accordance withvarious embodiments of the present disclosure.

DETAILED DESCRIPTION

The present disclosure relates to coexistence of radio frequency (RF)signals in communication devices such as, e.g., mobile communicationdevices. Coordination of different RF signals can reduce or eliminatemutual interference between the RF signals. Each communication devicecan include one or more radio transceiver(s). Typically, a transceiverincludes a data modulation stage and an RF stage. The data modulationstage (baseband process) converts data to baseband signals in accordancewith the particular wireless communication standard. The RF stage (e.g.,a transmitter section and/or receiver section) converts between basebandsignals and RF signals. The RF stage may convert directly from basebandto RF or may include one or more intermediate frequency stage(s).

Currently, IEEE 802.11 a/b/g/n (Wi-Fi) is the ubiquitous connectivitytechnology employed at home, work, and other venues through, e.g., awireless local area network (WLAN). Mobile communication devices suchas, e.g., mobile phones, tablet computers, electronic book readers, etc.may include Wi-Fi capabilities. Other communication devices such as,e.g., wireless routers and hotspot devices also support Wi-Ficapabilities. These communication devices may also support otherwireless communication technologies such as, e.g., Bluetooth (BT) and/orBT low energy (BTLE) to allow for communication with other devices thatsupport BT and/or BTLE. In addition, these communication devices maysupport cellular communications such as, e.g., a cellular dataconnection such as third-generation (3G), fourth-generation (4G), longterm evolution (LTE), or other data communication standard. For example,a communication device can offer tethering capabilities for sharing aLTE data connection with other communication devices over, e.g., a WLANfor Wi-Fi communications, a personal area network (PAN) for BT and/orBTLE communications, and/or other wireless connections. The tetheringservice can be capable of providing software enabled access point (AP)services as a “soft” access point (SoftAP). In such a configuration, thecommunication device supporting SoftAP may provide data communicationsover a WLAN connection to other wireless client stations (STAs).

The coexistence of an LTE communication signal with one or more of theother wireless communication signals can produce mutual interferencebetween the signals, resulting in degraded performance of the wirelesstechnologies. For instance, if the operating frequencies of the WLAN andLTE connections are close together, then the performance of bothtechnologies may be degraded due to mutual interference between the RFsignals. When LTE and WLAN coexist, simultaneous operation of an LTEinterface in a transmit (TX) mode and a WLAN interface in a receive (RX)mode can inhibit or prevent proper decoding of frames received over theWLAN connection due to the LTE transmissions. This can result in anincrease in the drop rate, elevated packet loss, and additionaltransmission retries. Similarly, transmissions over the WLAN may berestricted to protect LTE reception of data packets and/or frames.

With reference to FIG. 1, shown is a communication device 100 inaccordance with various embodiments of the present disclosure. Thecommunication device 100 may correspond to a handheld device, a mobiledevice, a desktop computer, a laptop computer, personal digitalassistants, cellular telephones, smartphones, set-top boxes, musicplayers, web pads, tablet computer systems, game consoles, electronicbook readers, wireless routers, hotspot devices or other devices withlike capability. The communication device 100 includes a communicationinterface 103, one or more wireless interface(s) such as, e.g., WLANinterface(s) 106, cellular network interface(s) 109, BT interface(s)112, and/or other components. The communication interface 103 may beconfigured to support wireless communication to wireless clients usingWi-Fi, Bluetooth, and/or other wireless technologies via the wirelessinterfaces 106, 109, and 112.

The communication interface 103 may coordinate communications throughthe different wireless interfaces 106, 109, and 112. For example, thecommunication interface 103 may provide wireless access point servicesas a “soft” access point (SoftAP) 115 or may provide services as awireless client station (STA) 118 that communicates with a wirelessaccess point (WAP) or another SoftAP. The WLAN interface(s) 106 maycorrespond to one or more interface(s) which are configured to supportWi-Fi communications. In some embodiments, multiple WLAN interfaces 106may be present to support multiple WLAN networks; multiple basic servicesets (BSS), etc. The cellular network interface(s) 109 may correspond toone or more interfaces which are configured to provide access to acellular network such as a 3G or 4G network, an LTE network, a WiMAXnetwork, and/or other types of networks. The cellular networkinterface(s) 109 can support high speed data transfer over the cellularnetwork. The BT interfaces 112 may correspond to one or moreinterface(s) which are configured to support BT and/or BTLEcommunications. The communication device 100 may also include othertypes of network interfaces such as, for example, Ethernet interfaces,universal serial bus (USB) network interfaces, token ring interfaces,and so on. In addition, the communication device 100 may be used forother activities such as, e.g., web browsing, gaming, and/or other userinteractive applications.

The communication interface 103 can monitor wireless communicationsthrough the wireless interfaces 106, 109, and 112 to determine whethercoordination of coexisting RF communications is needed to avoidinterference. The determination may be based upon one or more factor(s)such as, e.g., transmission frequencies, transmission powers, type ofcommunication, etc., which may be received from the different wirelessinterfaces 106, 109, and 112. For example, interference may be unlikelyfor specific combinations of wireless communications. When those definedconditions exist, the communication interface 103 may determine thatcoordination of the coexistent RF signals is not needed. In otherinstances, coordination of combinations of wireless communications maybe desired because of the proximity of the operational frequencies ofthe RF signals. For example, the coexistence of an LTE communicationsignal with WLAN, BT, and/or BTLE signals may result in mutualinterference. LTE communications can occur in band 7 (2500-2570 MHz and2620-2690 MHz) 203 or band 40 (2300-2400 MHz) 206, which are bothadjacent to the WLAN 2.4 GHz industrial, scientific and medical (ISM)band (2400-2500 MHz) 209 as illustrated in FIG. 2. If the frequencyseparation between the LTE and WLAN operating frequencies issufficiently large, then simultaneous transmission and/or reception maybe allowed without coordination of the LTE and WLAN communications.

Whether the separation between the operating frequencies of the RFsignals is sufficient for simultaneous communication may be determinedby comparing the frequency difference with a predefined threshold (e.g.,a threshold of X MHz). Different thresholds may be defined for differentcombinations of RF signals. In addition, the threshold value may beadjusted based at least in part upon the transmission power of the RFsignals. For example, the threshold value may be scaled or weightedbased at least in part upon the transmission powers of the RF signals.The separation between the operating frequencies may be less when one orboth of the signals are transmitted at a lower power level. In somecases, the transmit powers may be low enough to allow for coexistencewith minimal frequency separation. In some implementations, lookuptables may be used to determine the allowable frequency separation basedupon the transmission power levels.

In the case where the communication device 100 is acting as a SoftAP 115via an LTE connection, then the communication interface 103 cancoordinate the LTE and WLAN communications by setting up the BSS at achannel that sufficiently far away from the LTE operating frequencyreduce or avoid mutual interference. For example, if the LTE operatingfrequency 212 is at the edge of band 40 (206), then the BSS can be setupat a WLAN operating frequency 215 at the opposite end of the ISM band209 with a separation that is greater than the predefined threshold(e.g., >X MHz) as shown in FIG. 2. If the separation exceeds thepredefined threshold, then mutual interference may be considerednegligible and simultaneous transmission and/or reception of both RFsignals may be allowed. To minimize the mutual interference, the WLANchannel that is furthest from the LTE operating frequency 212 may beused. If the separation between the operating frequencies does not meetand/or exceed the predefined threshold, then further coordination of theRF signals may be needed to reduce the likelihood of mutualinterference. If the LTE operating frequency 218 is at the edge of band7 (203), then the BSS can be setup at a WLAN operating frequency 221 atthe opposite end of the ISM band 209 with a separation that is greaterthan the predefined threshold to minimize interference.

If the communication device 100 is a mobile communication device, thensituations may arise where the LTE operating frequency may switchbetween band 40 (206) and band 7 (203) because of handover. For example,the LTE communications may originally be carried out at operatingfrequency 212 in band 40 with WLAN communications at operating frequency215. If handover results in the LTE communications shifting from LTEoperating frequency 212 to LTE operating frequency 218 of band 7 (203),then the communication interface 103 can switch the WLAN communicationsfrom WLAN operating frequency 215 to WLAN operating frequency 221 toavoid interference. All connected STAs would automatically follow theWLAN operating frequency of the SoftAP 115 after connection loss. Inthis way, the communication interface 103 monitors the LTE operatingfrequency and dynamically switches the WLAN operating frequency toreduce mutual interference based at least in part upon the monitored LTEoperating frequency.

If the communication interface 103 determines that coordination ofcoexisting RF signals is needed to mitigate mutual interference, thentime domain coordination of the communications may be carried out by thecommunication interface 103. Initially, communication schedule(s) may beobtained by the communication interface 103. For example, a publishedLTE communication schedule may be communicated to the communicationinterface 103 by the cellular interface 109 implementing the LTEconnection. The LTE communication schedule indicates LTE transmission(TX) periods, LTE receive (RX) periods, and traffic free periods duringwhich no LTE communications are scheduled. When the communicationinterface 103 has information about the communication schedule, thecommunication interface 103 can coordinate the reception, transmission,and/or protection of other RF signals such as, e.g., WLAN signals. Insome situations, the communication interface 103 may determine thecommunication schedule by generating a predictor map based upon TX andRX indications received from the cellular interface 109 supporting theLTE or other cellular connection.

Referring to FIG. 3, shown is an example of an LTE predictor map 300generated from the indications of LTE-RX 303 and LTE-TX 306. The LTE-RX303 and LTE-TX 306 indications may be provided over a two-wireconnection where the LTE-RX 303 signal is asserted high when thecellular interface 109 is receiving LTE communications and the LTE-TX306 signal is asserted high when the cellular interface 109 istransmitting LTE communications. In the example of FIG. 3, the LTEpredictor map 300 includes an access identifier for each 1 ms LTEsubframe over a 10 ms window. In other implementations, differentsubframe lengths and/or window lengths may be used to map thecommunication schedule. The communication interface 103 determines theaccess identifier of each subframe based upon the LTE-RX 303 and LTE-TX306 signals. The access identifier indicates the communication statusduring the subframe period such as, e.g., LTE transmit (LTE-TX), LTEreceive (LTE-RX), no LTE transmit or receive traffic (LTE-Free), acombination of LTE transmissions, LTE receptions, and/or no LTE traffic(LTE-Special), or a combination of LTE receptions and no LTE traffic(LTE-RX/Free). The LTE predictor map 300 helps the communicationinterface 103 to coordinate coexisting LTE and WLAN signals by using thegenerated access pattern to predict the status of the next subframeperiod.

The communication interface 103 monitors LTE-RX 303 and LTE-TX 306signals for the duration of each subframe (e.g., a period of 1 ms) andat the end of the subframe period updates the subframe status based uponthe signal states. In the example of FIG. 3, the communication interface103 initially determines when a transition occurs in the LTE-RX 303and/or LTE-TX 306. In the example of FIG. 3, LTE-RX 303 goes high andLTE-TX 306 goes low at point 309. Because, LTE-RX 303 remains high andLTE-TX 306 remains low over the entire subframe period, the accessidentifier for subframe 311 is LTE-RX. Because LTE-RX 303 transitions tolow during subframe 312 and LTE-TX 306 transitions to high at the end ofthe subframe period, the access identifier for subframe 311 isLTE-Special, which indicates that both reception and transmission arepossible during that subframe period. The access identifiers forsubframes 313 and 314 are LTE-TX because LTE transmission is maintaineduntil the end of subframe 314, when LTE-TX 306 transitions to low. Theaccess identifier for subframe 315 is LTE-Free since no LTEcommunications occur over the subframe period.

LTE-RX 303 is high over subframe 316, indicating that the communicationdevice 100 is scheduled to receive LTE signals. LTE-RX 303 goes lowduring subframe 317 and remains low until the end of subframe 320.Because no LTE communications occur for the second portion of subframe317 and over the period of subframe 318, the access identifier forsubframe 317 is LTE-RX/Free and the access identifier for subframe 318is LTE-Free. At the beginning of subframe 319, LTE-TX 306 goes high andremains high until the end of the window where LTE-RX 303 goes high andLTE-TX 306 goes low just as at point 309. Accordingly, the accessidentifiers for both subframes 319 and 320 are LTE-TX. In this way, thecommunication interface 103 can generate an LTE predictor map 300including the access identifiers for ten subframes 311-320. The LTEpredictor map 300 may be used to predict the access pattern and thus thestatus of the next LTE subframe(s), allowing the communication interface103 to coordinate the WLAN (or other) communications.

The LTE-RX 303 and LTE-TX 306 indications provided over the two-wireconnection may also be used to predict the LTE measurement gap, whichmay be used for periodic WLAN scans. For a WLAN periodic active scan, aSTA sends a probe request message and waits for a probe response messageto be returned from an AP within a defined time period. When acommunication device 100 acting as a STA 118, the probe response messagemay not be properly decoded if there is an LTE transmission at the sametime. To avoid this situation, periodic scanning may be performed duringthe LTE measurement gap, where the cellular interface 109 is also in areceive mode. The LTE measurement gap has a duration from about 6 ms toabout 7 ms at an interval of about 40 ms or about 80 ms. Thecommunication interface 103 can monitor the LTE-RX 303 indication tofind when it is asserted high for about 6 ms to about 7 ms. By assumingthat this is the LTE measurement gap, the gap interval may be confirmedby monitoring for the LTE measurement gap over 4-5 gap intervals (about160 ms to about 400 ms). Based upon the predicted LTE measurement gaplength and interval, the communication device 100 can wait for the LTEmeasurement gap to improve the success of the periodic scanning. Inaddition, the LTE predictor map 300 should not be updated for thesubframes where the LTE measurement gap is observed.

Various schemes may be utilized to reduce or eliminate mutualinterference between coexisting RF signals. The transmission and/orreception of the coexisting RF signals may be coordinated by thecommunication interface 103 based upon the communication schedule(s)and/or the predictor map to aid in proper reception and decoding of thetransmitted packets and/or frames. Some or all of the schemes may beapplied when the communication device 100 is acting as a SoftAP 115and/or as a STA 118.

Referring to FIG. 4, shown is an example of a networked environment 400including a communication device 100 with coexisting Wi-Fi and cellularcommunications. In the example of FIG. 4, the communication device 100is providing wireless access point services as a SoftAP 115 to one ormore Wi-Fi client station (STA) 403 that are communicatively coupled viaan IEEE 802.11 a/b/g/n network such as, e.g., WLAN 406 or other similarwireless network. Each of the STAs 403 may correspond to a handhelddevice, a mobile device, a desktop computer, a laptop computer, personaldigital assistant, cellular telephone, smartphone, set-top box, musicplayer, web pad, tablet computer system, game console, electronic bookreader, or other devices with like capability.

The communication device 100 is also communicatively coupled to acellular base station 409 via cellular network 412. The cellular network412 may correspond to, e.g., an LTE or WiMAX network. Acting as a SoftAPallows the communication device 100 to facilitate tethering the one ormore STAs 403 through the cellular connection such as, e.g., an LTE dataconnection. Tethering allows the STAs 403 to access resources providedby through the cellular network 412 and base station 409. For example,the cellular base station 409 may provide connectivity to the Internetand/or another network for the communication device 100.

When Wi-Fi transmissions from a STA 403 occur during LTE or othercellular transmissions by the communication device 100, the SoftAP 115may not be able to acknowledge (ACK) the received frames or packetsbecause of mutual interference between the coexisting WLAN and LTEsignals. Because the SoftAP 115 may not be able to properly decodereceived frames because of the LTE transmissions, this may result inretry, rate drop, and/or packet loss at the STA 403. To avoid theeffects of mutual interference, the communication interface 103 cancoordinate WLAN communications so that frames or packets are receivedfrom the STAs 403 during an LTE-RX or LTE-Free subframe. Reversedirection protocol (RDP) and/or clear-to-send to self (CTS2self)messaging may be used for time domain coordination of the coexisting RFsignals.

Referring to FIG. 5, shown is an example of the coordination ofcoexistent Wi-Fi and cellular communications using a reverse directiongrant (RDG) when the communication device 100 is acting as a SoftAP 115for one or more STA(s) 403 of the WLAN 406 (FIG. 4). When a STA 403transmits during a transmission period of the cellular interface 109,the SoftAP 115 may not be able to acknowledge the frames because ofmutual interference between the RF signals. The SoftAP 115 may not beable to properly decode the frames during the cellular transmissionperiod, causing retry, rate drop, and possible packet loss. To avoidissues with mutual interference, the communication interface 103 cancoordinate the coexisting RF communications during a traffic free periodof the cellular communications.

In the example of FIG. 5, the communication interface 103 may obtain thecommunication schedule for an LTE connection by, e.g., generating an LTEpredictor map 300 (FIG. 3). Based upon the LTE communication schedule,the communication interface 103 can determine that the next traffic free(LTE-Free) subframe period 503 of the LTE communications falls between,e.g., transmitting and/or receiving frames (LTE-TX/RX) 506. At thebeginning of the LTE-Free subframe period 503, the SoftAP 115 of thecommunication device 100 and the STAs 403 of the WLAN 406 (FIG. 4)attempt to obtain contention free access to the WLAN communicationchannel during a contention phase 509. Enhanced distributed channelaccess (EDCA) parameters may be set to give the SoftAP 115 a betterchance of obtaining access of the WLAN channel than the STA(s) 403 ofthe WLAN 406. For example, the arbitration inter-frame space (AIFS) ofthe SoftAP 115 may be the sum of a short inter-frame space (SIFS) andtwo slot times while the AIFS of the STAs 403 may be the sum of the SIFSand a larger AIFS number of slot times. A transmit opportunity (TXOP) ofthe SoftAP 115 may be set to 10 ms for all access categories (AC) andthe TXOP of the STAs 403 may be set to 0 ms for best effort (BE) andless than 1 ms for video (VI) and voice (VO). The minimum and maximumcontention windows (CWs) for the SoftAP 115 may be CW_(min)=7 andCW_(max)=15 for BE, CW_(min)=1 and CW_(max)=3 for VI, and CW_(min)=3 andCW_(max)=7 for VO and the CWs for the STAs 403 CW_(min)=31 andCW_(max)=1023 for BE, CW_(min)=7 and CW_(max)=15 for VI, and CW_(min)=15and CW_(max)=31 for VO. By utilizing these EDCA parameters, the SoftAP115 can obtain contention free access to the WLAN channel and maximizethe utilization of the LTE-Free periods by avoiding further contentionbetween the STAs 403.

Once the contention phase 509 is resolved, the SoftAP 115 may use areverse direction grant (RDG) 512 to allow a STA 403 to transmit overthe WLAN channel for a duration corresponding to at least a portion of aTXOP 515 of the LTE-Free subframe period 503. In the example of FIG. 5,the TXOP 515 extends from the end of the contention phase 509 to the endof the LTE-Free subframe period 503. The SoftAP 115 sends a RDG frame512 a to a STA 403 a after obtaining contention free access to the WLANchannel. The RDG frame 512 a grants the use of the WLAN channel to theSTA 403 a for a duration less than or equal to remaining portion of theTXOP 515 of the LTE-Free subframe period 503 at the time of the receiptof the RDG grant. The RDG frame 512 a may include a RDG flag that is setto 1 to indicate a reverse direction grant is provided to the designatedSTA 403 and/or a duration field in a MAC header specifying the durationduring which the STA 403 may transmit. The duration is set such that theSTA transmission ends before the next LTE-TX/RX subframe period 506starts.

With the grant of RDG frame 512 a, the STA 403 a may then transmit oneor more frames 518 a for at least a portion of the duration. Frames 518a may contain acknowledgement information for RDG frame 512 a, inaddition to any new frames that are being sent from STA 403 a to SoftAP115. If the frames 518 a of the STA 403 a exceed the specified duration(e.g., duration=TXOP 515), then the frames 518 a may be broken intoparts for transmission. If the STA 403 a does not have enough frames 518a to utilize the entire duration, then the SoftAP 115 may grant accessto another STA 403 b for the remaining portion of the TXOP 515. When theframes 518 a have been received from the STA 403 a, the SoftAP 115 sendsan acknowledgement (ACK) 521 a or block acknowledgement (BlockACK)confirming receipt and then may send another RDG frame 512 b to anotherSTA 403 b to grant the use of the WLAN channel for the remaining portionof the TXOP 515 (e.g., duration=RemTXOP 524). With the grant of RDGframe 512 b, the other STA 403 b may then transmit one or more frames518 b for at least a portion of RemTXOP 524. When the frames arereceived, the SoftAP 115 sends an acknowledgement (ACK) 521 b (orBlockACK). As with STA 403 a, frames may be separated so that thespecified duration is not exceeded. If a portion of the TXOP 515 stillremains after transmission of the frames 518 b, the remaining portionmay be granted to a third STA 403 as can be understood.

Mutual interference may also be avoided by restricting transmissions ofthe STAs 403 during transmission periods of the cellular interface 109.Referring to FIG. 6, shown is an example of the coordination ofcoexistent Wi-Fi and cellular communications using a clear-to-send toself (CTS2self) frame when the communication device 100 is acting as aSoftAP 115 for one or more STA(s) 403 of the WLAN 406 (FIG. 4). Basedupon the communication schedule, the communication interface 103 candetermine that the next transmission (LTE-TX) subframe period 603 of theLTE communications falls between, e.g., receiving and/or traffic freeframes (LTE-RX/Free) 606. To prevent the STAs 403 from transmittingduring the LTE-TX subframe period 603, the SoftAP 115 may send aCTS2self frame 609 after obtaining contention free access of the WLANchannel during contention phase 612. The CTS2self frame 609 is sent inthe beginning of the LTE-TX subframe period 603 with a duration field inthe MAC header set to the length of the LTE-TX subframe period 603,which is less than or equal to TXOP 615. When the STAs 403 receive theCTS2self frame 609, the STAs 403 update their network allocation vector(NAV) with the duration specified in CTS2self frame 609 and defer theirtransmissions until after the duration has passed. By sending theCTS2self frame 609 in the beginning of the LTE-TX subframe period 603,the SoftAP 115 makes sure that none of the STAs 403 transmit framesduring the LTE-TX subframe period 603. In this way, mutual interferencebetween the WLAN and LTE transmissions is avoided, reducing the retry,rate drop, and packet loss that may occur otherwise.

In another implementation, a combination of RDG and CTS2self frames mayalso be used to prevent a STA transmission from occurring during atransmission period of the coexisting cellular connection as illustratedin FIG. 7. Based upon the LTE communication schedule, the communicationinterface 103 can determine when a traffic free (LTE-Free) subframeperiod 703 will occur before a transmission (LTE-TX) subframe period 706of the LTE communications. At the beginning of the LTE-Free subframeperiod 703, the SoftAP 115 of the communication device 100 (FIG. 4)obtains contention free access to the WLAN communication channel duringa contention phase 709. The SoftAP 115 sends a RDG frame 712 to a STA403 c granting the use of the WLAN channel to the STA 403 c for aduration equal to a TXOP Grant 715. The duration can be set such thatSoftAP 115 does not have to contend again for sending a CTS2self frame721 to avoid transmissions during the following LTE-TX subframe period706 (e.g., TXOP Grant 715=TXOP 718—SIFS—duration of a CTS2self frame721). The duration is set such that the STA transmission allows for theCTS2self frame 721 to be transmitted at the beginning of the followingLTE-TX subframe period 706.

With the grant of RDG frame 712, the STA 403 c may then transmit one ormore frames 724 for at least a portion of the duration. When the frames724 have been received from the STA 403 c, the SoftAP 115 sends anacknowledgement (ACK) 727 (or BlockACK) confirming receipt. After theACK 727 is sent in FIG. 7, the SoftAP 115 may send a CTS2self frame 721in the beginning of the LTE-TX subframe period 706 with the durationfield in the MAC header set to the length of the LTE-TX subframe period706. When the STAs 403 of the WLAN 406 receive the CTS2self frame 721,the STAs 403 update their NAV with the duration specified in CTS2selfframe 721 and defer their transmissions until after the duration haspassed.

It should be noted that if the STA 403 c does not have enough frames 724to utilize the entire duration, then the SoftAP 115 may grant access toanother STA 403 (not shown) for the remaining portion of the TXOP Grant715 similar to the example of FIG. 5.

In some cases, the SoftAP 115 may not grant the remaining portion of theTXOP Grant 715 to another STA 403 after sending the ACK 727. In thissituation, the SoftAP 115 may send the CTS2self frame 721 before thebeginning of the LTE-TX subframe period 706 with the duration field setto the length of the LTE-TX subframe period 706 plus the intervalbetween sending the CTS2self frame 721 and the beginning of the LTE-TXsubframe period 706. By sending the CTS2self frame 721, the SoftAP 115makes sure that none of the STAs 403 transmit frames until after theLTE-TX subframe period 706.

Referring next to FIG. 8, shown is an example of a networked environment800 including a communication device 100 with coexisting Wi-Fi andcellular communications. In the example of FIG. 8, the communicationdevice 100 is acting as a Wi-Fi client station (STA) 118 communicativelycoupled to an access point (AP) 803 (e.g., a wireless AP or SoftAP)through a WLAN 806. One or more other STAs 809 may also becommunicatively coupled to the AP 803 through WLAN 806. Each of the STAs403 may correspond to a handheld device, a mobile device, a desktopcomputer, a laptop computer, personal digital assistant, cellulartelephone, smartphone, set-top box, music player, web pad, tabletcomputer system, game console, electronic book reader, or other deviceswith like capability.

The communication device 100 is also communicatively coupled to acellular base station 812 via cellular network 815. The cellular network815 may correspond to, e.g., an LTE or WiMAX network. When Wi-Fitransmissions from AP 803 occur during LTE or other cellulartransmissions by the communication device 100, the STA 118 may not beable to acknowledge (ACK) the received frames or packets because ofmutual interference between the coexisting WLAN and LTE signals. Toavoid the effects of mutual interference (e.g., retry, rate drop, and/orpacket loss), the communication interface 103 can coordinate WLANcommunications so that frames or packets are received by the STAs 403during an LTE-RX or LTE-Free subframe. RDP and/or CTS2self messaging mayagain be used for time domain coordination of the coexisting RF signals.

Referring to FIG. 9, shown is an example of the coordination ofcoexistent Wi-Fi and cellular communications using a RDG when thecommunication device 100 is acting as a STA 118 of the WLAN 806 (FIG.8). When the AP 803 transmits during a transmission period of thecellular interface 109, the STA 118 may not be able to acknowledge theframes because of mutual interference between the RF signals. The STA118 may not be able to properly decode the frames during the cellulartransmission period, causing retry, rate drop, and possible packet loss.To avoid issues with mutual interference, the communication interface103 can coordinate the coexisting RF communications during a trafficfree period of the cellular communications.

In the example of FIG. 9, the communication interface 103 may obtain thecommunication schedule for an LTE connection to determine that the nexttraffic free (LTE-Free) subframe period 903 of the LTE communicationsfalls between, e.g., transmitting and/or receiving frames (LTE-TX/RX)906. At the beginning of the LTE-Free subframe period 903, the STA 118of the communication device 100 and the AP 803 and other STAs 809 of theWLAN 806 (FIG. 8) attempt to obtain contention free access to the WLANcommunication channel during a contention phase 909. Once the contentionphase 909 is resolved, the STA 118 may use a RDG 912 to allow the AP 803to transmit over the WLAN channel for a duration corresponding to atleast a portion of a TXOP 915 of the LTE-Free subframe period 503. Inthe example of FIG. 9, the TXOP 915 extends from the end of thecontention phase 909 to the end of the LTE-Free subframe period 903.

The STA 118 sends a RDG frame 912 to AP 803 after obtaining contentionfree access to grant the use of the WLAN channel to the AP 803 for aduration equal to the TXOP 915 of the LTE-Free subframe period 903. TheRDG frame 912 may include a RDG flag that is set to 1 to indicate areverse direction grant is provided to the AP 803 and/or a durationfield in a MAC header specifying the duration during which the AP 803may transmit. The duration is set such that the AP transmission endsbefore the next LTE-TX/RX subframe period 906 starts. With the grant ofRDG frame 912, the AP 803 may then transmit one or more frames 918 forat least a portion of the duration. When the frames 918 have beenreceived from the AP 803, the STA 118 sends an acknowledgement (ACK) 921(or BlockACK) confirming receipt. Frames 918 may contain acknowledgementinformation for RDG frame 912, in addition to any new frames that arebeing sent from AP 803 to STA 118. If the AP 803 does not have enoughframes 918 to utilize the entire duration, then the STA 118 may use theremaining portion of the TXOP 918 (RemTXOP 924) to transmit frames 927to AP 803. When the frames are received, the AP 803 sends anacknowledgement (ACK) 930 (or BlockACK).

Mutual interference may also be avoided by restricting transmissions ofthe AP 803 during transmission periods of the cellular interface 109.Referring to FIG. 10, shown is an example of the coordination ofcoexistent Wi-Fi and cellular communications using a CTS2self frame whenthe communication device 100 is acting as a STA 118 of the WLAN 806(FIG. 8). Based upon the LTE communication schedule, the communicationinterface 103 can determine that the next transmission (LTE-TX) subframeperiod 1003 of the LTE communications falls between, e.g., receivingand/or traffic free frames (LTE-RX/Free) 1006. To prevent the AP 803from transmitting during the LTE-TX subframe period 1003, the STA 118may send a CTS2self frame 1009 after obtaining contention free access ofthe WLAN channel during contention phase 1012. The CTS2self frame 1009is sent in the beginning of the LTE-TX subframe period 1003 with aduration field in the MAC header set to the length of the LTE-TXsubframe period 1003, which is less than or equal to TXOP 1015. When theAP 803 receives the CTS2self frame 1009, the AP 803 defers itstransmissions by the duration specified in CTS2self frame 1009. Bysending the CTS2self frame 1009 in the beginning of the LTE-TX subframeperiod 1003, the STA 118 makes sure that the AP 803 won't transmitframes during the LTE-TX subframe period 1003. In this way, mutualinterference between the WLAN and LTE transmissions is avoided, reducingthe retry, rate drop, and packet loss that may occur otherwise.

Referring next to FIG. 11, shown is an example of the coordination ofcoexistent Wi-Fi and cellular communications using a null data framewhen the communication device 100 is acting as a STA 118 of the WLAN 806(FIG. 8). To prevent the AP 803 from transmitting during the LTE-TXsubframe period 1003, the STA 118 may send a null data frame 1109 aafter obtaining contention free access of the WLAN channel duringcontention phase 1112 a. The null data frame 1109 a is sent in thebeginning of the LTE-TX subframe period 1003 to indicate that the STA118 is entering a power save mode. For example, the null data frame 1109a may include a power mode (PM) bit that when set to “1” indicates thepower save mode. When the AP 803 receives the null data frame 1109 a, AP803 stops transmitting to the STA 118 and starts buffering the traffic.

Once the LTE-TX subframe period 1003 is over, the STA 118 transmitsanother null data frame 1109 b that indicates that the STA 118 is comingout of the power save mode. For example, the PM bit may be set to “0” toindicate that the STA 118 is no longer in the power save mode. In theexample of FIG. 11, the null data frame 1109 b is sent after acontention phase 1112 b and an ACK 1115 is sent by the AP 803 afterreceiving the null data frame 1109 b indicating that the STA 118 iscoming out of the power save mode. The AP 803 may then resumetransmission of the buffered traffic. By sending the null data frame1109 a in the beginning of the LTE-TX subframe period 1003 and the nulldata frame 1109 b at the end of the LTE-TX subframe period 1003, the STA118 makes sure that the AP 803 won't transmit frames during the LTE-TXsubframe period 1003. In this way, mutual interference between the WLANand LTE transmissions is avoided, reducing the retry, rate drop, andpacket loss that may occur otherwise.

To improve the chance of obtaining contention free access to the WLANchannel during the contention phase 1112, a null data frame 1109 with apoint inter-frame space (PIFS) and a small backoff may be used. Forexample, instead of using a distributed inter-frame space (DIFS)+VO AC[CW window], PIFS+small random backoff parameters [CW_(min)=1,CW_(max)=3] may be used. Using the PIFS and the small backoff improvesthe chance of STA 118 acquiring contention free access for sending thenull data frame 1109.

In another implementation, a combination of RDG and null data frames mayalso be used to prevent an AP transmission from occurring during atransmission period of the coexisting cellular connection as illustratedin FIG. 12. Based upon the LTE communication schedule, the communicationinterface 103 can determine when a traffic free (LTE-Free) subframeperiod 1203 will occur before a transmission (LTE-TX) subframe period1206 of the LTE communications. At the beginning of the LTE-Freesubframe period 1203, the STA 118 of the communication device 100 (FIG.8) obtains contention free access to the WLAN communication channelduring a contention phase 1209. The STA 118 sends a RDG frame 1212 tothe AP 803 (FIG. 8) granting the use of the WLAN channel to the AP 803for a duration equal to a TXOP Grant 1215. The duration can be set suchthat STA 118 does not have to contend again for sending a null dataframe 1218 to avoid transmissions during the following LTE-TX subframeperiod 1206 (e.g., TXOP Grant 1215=TXOP 1221−SIFS−duration of a nulldata frame 1218−duration of an ACK frame 1224). The duration is set suchthat the STA transmission allows for the null data frame 1218 and ACK1224 to be transmitted at the beginning of the following LTE-TX subframeperiod 1206.

With the grant of RDG frame 1212, the AP 803 may then transmit one ormore frames 1227 for at least a portion of the duration. When the frames1227 have been received from the STA 118, the STA 118 sends anacknowledgement (ACK) 1230 (or BlockACK) confirming receipt. After theACK 1230 is sent in FIG. 12, the STA 118 may send a null data frame 1218to indicate that the STA 118 is entering a power save mode (e.g., PM=1).An ACK 1224 is sent by the AP 803 after receiving the null data frame1218 and AP 803 stops transmitting to the STA 118 and starts bufferingthe traffic. Once the LTE-TX subframe period 1206 is over, the STA 118can transmit another null data frame (not shown) that indicates that theSTA 118 is coming out of the power save mode (e.g., PM=0). The AP 803may then resume transmission of the buffered traffic.

In some situations, concurrent WLAN and cellular transmissions may occurwhen the communication device 100 is acting as a SoftAP 115 to a STA 403as in FIG. 4 or as a STA 118 in communication with an AP 803 as in FIG.8. When an acknowledgment (ACK) to the WLAN transmission is sent duringthe cellular transmission, then the ACK may not be decoded properlywhich can result in retry, rated drop, and/or packet loss. Bycoordinating the WLAN communications such that the ACK is sent during areceive period or traffic free period that follows the cellulartransmission period, interference between the WLAN and cellulartransmissions may be avoided.

Referring to FIG. 13, shown is an example of the coordination ofcoexistent Wi-Fi and cellular communications using a CTS2self frame whenthe communication device 100 is acting as a SoftAP 115 or a STA 118. Inthe example of FIG. 13, the communication device 100 may transmit, e.g.,MAC protocol data units (MPDUs) and/or aggregated MPDUs (AMPDU) over aWLAN channel during an LTE transmission (LTE-TX) subframe period 1303.To improve the success of the WLAN transmission, the transmitted datamay be aligned within the LTE-TX subframe period 1303 such that the ACKis sent during the following receive or traffic free (LTE-RX/Free)subframe period 1306. In the example of FIG. 13, the SoftAP 115 or STA118 obtains contention free access of the WLAN channel during acontention phase 1309.

After obtaining access, the SoftAP 115 or STA 118 may send a CTS2selfframe 1312 with a duration field in the MAC header set to the length ofthe remaining LTE-TX period 1315+SIFS+duration of an ACK frame 1318. Bysending the CTS2self frame 1312, the SoftAP 115 makes sure that theother STAs 403 (FIG. 4) won't transmit for the specified duration.Similarly, by sending the CTS2self frame 1312, the STA 118 makes surethat the AP 803 (FIG. 8) won't transmit for the specified duration.Based upon the number of MPDUs that are buffered for transmission andthe modulation and coding scheme (MCS) rate, the number of MPDUs thatmay be transmitted within the specified duration can be determined. Ifmultiple MPDUs may be transmitted, an AMPDU (including delimiter) may beformed for transmission. As shown in FIG. 12, transmission of the MPDUor AMPDU 1321 is started by the SoftAP 115 or STA 118 such that it endswithin a SIFS period of the boundary 1324 between LTE-TX subframe 1303and LTE-RX/Free subframe 1306. In this way, the ACK 1318 (or BlockACK)is received during the following LTE-RX/Free subframe period 1306.

Referring next to FIG. 14, shown is another example of the coordinationof coexistent Wi-Fi and cellular communications using an acknowledgementpolicy when the communication device 100 is acting as a SoftAP 115 or aSTA 118. In the example of FIG. 14, an acknowledgement request is usedto delay the transmission of the BlockACK (or ACK) until after theLTE-TX subframe period 1403. After obtaining contention free access ofthe WLAN channel during a contention phase 1409, the SoftAP 115 or STA118 may send a MPDU or AMPDU 1412 at any time during the LTE-TX subframeperiod 1403. With the acknowledgement policy, an ACK (or BlockACK) isnot expected to be sent until requested by the SoftAP 115 or STA 118. Asshown in FIG. 14, the SoftAP 115 or STA 118 sends an ACK request 1418(or BlockACK request) after a contention phase 1415. In response, theSTA 403 or AP 803 sends the ACK 1421 (or BlockACK) during the LTE-Freesubframe period 1406 to confirm receipt of the MPDU or AMPDU 1412 duringthe LTE-TX subframe period 1403. In this way, interference of the ACK1421 is avoided.

Referring next to FIGS. 15A and 15B, shown are flowcharts that provideexamples of coordination of coexisting WLAN and cellular communicationsin accordance with various embodiments of the present disclosure. It isunderstood that the flowcharts of FIGS. 15A and 15B provide merelyexamples of the many different arrangements that may be employed forcoexisting WLAN and cellular communications as described herein. As analternative, the flowcharts of FIGS. 15A and 15B may be viewed asdepicting examples of steps of methods implemented in the communicationdevice 100 (FIGS. 4 and 8) according to one or more embodiments.

Referring now to FIG. 15A, beginning with 1503 access to a WLAN channelmay be obtained by a communication device 100 supporting coexistingwireless local area network (WLAN) and cellular communications. Theaccess to the WLAN channel is contention free access during a trafficfree period of the coexisting cellular connection. A reverse directiongrant (RDG) is provided but the communication device 100 to anotherdevice of the WLAN in 1506 allowing the other device to transmit overthe WLAN channel for a duration corresponding to at least a portion of atransmit opportunity (TXOP) of the traffic free period of the coexistingcellular connection. In 1509, the transmission from the other WLANdevice is received. After reception of the transmission, if a portion ofthe TXOP was not utilized, then the communication device 100 may grantaccess to the WLAN channel to another WLAN device in 1512. The flowwould then return to 1506, where another RDG is provided to allow thetransmission. In other implementations, the communication device 100 maynot grant access to another WLAN device 1512. In that case, thecommunication device 100 may utilize access to the WLAN channel for itsown transmissions.

Referring to FIG. 15B, beginning with 1521 access to a WLAN channel maybe obtained by a communication device 100 supporting coexisting wirelesslocal area network (WLAN) and cellular communications. The access to theWLAN channel is contention free access during a transmission period of acoexisting cellular connection. After obtaining access, a protectionframe is provided to at least one other device of the WLAN to defertransmissions for a duration corresponding to at least a portion of atransmit opportunity (TXOP) of the transmission period of the coexistingcellular connection. In some embodiments, the protection frame may be aCTS2self frame transmitted at the beginning of the transmission periodthat indicates a duration corresponding to the TXOP of the transmissionperiod. In other embodiments, the protection frame may be a null dataframe indicating that the communication device 100 is entering a powersave mode. A subsequent null data frame may be sent to indicate when thecommunication device is exiting the power save mode.

Referring next to FIG. 16, shown is an example of a networkedenvironment 1600 including a communication device 100 with coexistingBluetooth (BT) or BT low energy (BTLE) and cellular communications. Inthe example of FIG. 16, the communication device 100 is communicativelycoupled to one or more BT client(s) 1603 via a personal area network(PAN) 1606 such as a piconet. Each of the BT client(s) 1603 maycorrespond to a handheld device, a mobile device, a desktop computer, alaptop computer, personal digital assistant, cellular telephone,smartphone, set-top box, music player, headset, or other devices withlike capability. The communication device 100 is also communicativelycoupled to a cellular base station 1609 via cellular network 1612. Thecellular network 1612 may correspond to, e.g., an LTE or WiMAX network.For example, the cellular base station 409 may provide connectivity tothe Internet and/or another network for the communication device 100.

By knowing the communication schedule of the cellular interface 109, thecommunication interface 103 can use this knowledge to schedule BT and/orBTLE traffic to meet less interference and have better throughput. Forexample, a published LTE communication schedule may be communicated bythe cellular interface 109 implementing the LTE connection or apredictor map may be generated based upon TX and RX indications from thecellular interface 109. BT communications are carried out over a channelthat is time divided with a slot granularity of 0.625 ms where a mastertransmits during odd slots and a slave transmits during even slots. EachBT packet can occupy one, three or five slots. The BT interface 112 ofthe communication device 100 may transmit BT or BTLE traffic during anLTE-TX (or uplink) subframe period or may receive BT or BTLE trafficduring an LTE-RX (or downlink) subframe period to avoid mutualinterference. Since the extended synchronous connection oriented (eSCO)link is a periodic traffic and the LTE frame is 10 ms, there is aduration (or pattern periodicity) after which positioning of the BT orBTLE traffic with respect to the LTE frame would repeat. By determiningthe scheduling pattern of the BT or BTLE traffic for the duration of thepattern periodicity, the entire duration of the BT/BTLE and LTEcoexistence may be coordinated.

BT eSCO comes with a strict requirement of having one RX-TX transactionper TeSCO interval. WeSCO defines the number of retransmissions that maybe allowed. FIG. 17 shows an example illustrating the relationshipbetween TeSCO and WeSCO. In the example of FIG. 17, TeSCO=6 (with aninterval of 3*1.25 ms), WeSCO=2 and the packet type is EV3. The S1transaction window 1703 has a 1.25 ms duration and starts with an offsetof zero, the S2 window 1706 starts with an offset of 1.25 ms, the S3window 1709 starts with an offset of 2.5 ms, and each of S1 1703, S21706 and S3 1709 are 1.25 ms in duration with a RX slot and a TX slot.For A2DP/ACL, S1, S2, S3 convention is used to indicate consecutive 1.25ms of Tx-Rx pair slots. BT SCO HV3 packets are only allowed transmissionat S1 1703. But in a coexistence scenario or with high interference,retransmissions may be needed to compensate for failures during the S1window 1703. An eSCO packet type supports retransmission. If thetransaction at S1 1703 fails, the transaction is tried again at S2 1706;and if that fails as well then it is tried again at S3 1709. Byselecting the window (S1/S2/S3) such that the first transaction in aneSCO window goes out error-free, a reduction in power consumption by thetransmitter and a reduction of interference with LTE communications canbe achieved.

Bluetooth eSCO packets are sent out in every TeSCO interval, which arenegotiated during the eSCO connection setup. For every TeSCO interval inthe pattern periodicity, the BT might not get any of the S1, S2, or S3transaction windows because of the coexistent LTE communications. FIG.18A illustrates an example of a conflict between BT communications andLTE communications with the communication device 100 supporting BTcommunications as, e.g., a slave. The BT RX-TX transaction 1803 can bescheduled in S1 transaction window of the first TeSCO interval 1806without conflicting with the LTE communications. In the second TeSCOinterval 1809, a conflict occurs between the LTE-TX 1812 and the BTRX-TX transaction in the S1 transaction window and between the LTE-RX1815 and the BT RX-TX transaction 1818 in the S2 and S3 transactionwindows. Because of this, BT RX-TX transaction 1818 cannot be scheduledin the S1, S2, or S3 transaction windows of the second TeSCO interval1809.

However, by shifting the TeSCO intervals with respect to the start ofthe LTE frame, the BT RX-TX transactions 1803 and 1818 in the patternperiodicity can be scheduled. The shift can be determined with respectto the LTE transmit and receive pattern of the LTE communicationschedule. Referring to FIG. 18B, shown is a BT shift 1821 of the BTRX-TX transaction 1818. By shifting the TeSCO intervals to lead the LTEframe start by 1 ms; the BT RX-TX transaction 1803 can be scheduled inS2 window of the first TeSCO interval 1806 and the BT RX-TX transaction1818 can be scheduled in S2 window of the second TeSCO interval 1809. Bydetermining a unique BT shift of the TeSCO intervals with respect to LTEframe start, it is possible for all BT RX-TX transactions in the patternperiodicity to go through. Shifting the BT RX-TX transactions can helpBT traffic which is periodic in nature.

In other implementations, one or both of the RX and/or TX portions ofthe BT TX-RX transaction may be individually shifted to allow forscheduling. Referring to FIGS. 19A and 19B, BT communications work witha slot granularity of 0.625 ms with the TX-RX transaction 1903including, e.g., a TX portion 1906 followed by a RX portion 1909 duringa transaction window of 1.25 ms. If the communication device 100 issupporting BT communications as, e.g., a master, it would TX at evenslots and RX at odd slots. BT client(s) 1603 (FIG. 16) operating as aslave would TX at odd slots. BT packets can be of 1, 3 or 5 slotduration. Referring to FIG. 19A, shown is an example of scheduling ofTX-RX transactions 1903 in light of an LTE communication schedule. Asshown in the example of FIG. 19A, a LTE-TX subframe period 1912 isfollowed by three LTE-RX subframe periods 1915. As illustrated in FIG.19A, the even slot may not be available for BT RX 1909 during the S1transaction window or odd slots may not be available for BT TX 1906during the S2 and S3 transaction windows.

As shown in FIG. 19B, the RX portion 1909 may be shifted 1921 to a slotthat occurs during the LTE-RX subframe periods 1915 and/or an LTE-Freesubframe period. In this way, conflicts between the BT communicationsand the LTE cellular communications can be avoided. Even with a smallpayload size that would only occupy one slot for BT TX portion 1906, apacket type may be defined that takes up three or five slots fortransmission but with the payload (e.g., 1918 of FIG. 19B) adjusted suchthat airtime is only for one slot. Even though the packet type isdefined to take up three or five slots for transmission, the payloadsize may be adjusted intelligently to occupy other airtimes such as,e.g., an airtime that coincides with the LTE-TX subframe period 1912.This would offset the start of the BT RX portion 1909 by two or fourslots, respectively. The packet type used to affect the desired shiftcan be based at least in part upon the LTE transmit and receive patternof the LTE communication schedule. In the example of FIG. 19B, the BT TXpacket has been defined for three slots, which shifts 1921 the BT RXportion 1909 over by two slots into LTE-RX subframe periods 1915. Thepayload 1918 is transmitted during the first slot. The use ofnon-consecutive slots for the TX-RX transaction 1903 can be beneficialfor bursty traffic like ACL (asynchronous connection less). Based on theavailability of durations to do either a BT TX portion 1906, a BT RXportion 1909, or both (idle slots), packet types and payload may bedefined to allow for an interference-free transaction to be completed.

Coexistent cellular communications may also inhibit the establishment ofa BT connection between the communication device 100 and another BTclient 1603 (FIG. 16) by interfering with the paging sequence. Toestablish a BT link, a master sends a page message at a number offrequencies about a frequency f(k) at which the slave is predicted to belistening. The train A includes the 16 frequencies surrounding thepredicted frequency (i.e., {f(k−8), . . . f(k), . . . , f(k+7)}) andtrain B includes the remaining frequencies. In the next slot, a pageresponse is sent by the slave in response to the page message. Themaster then sends its frequency hopping sequence (FHS) packet to theslave in the next slot informing the slave of the master clock, which isused to determine a clock offset for synchronization of the slave clock.As illustrated in the example of FIG. 20, the clock offset 2003 is addedto the output of a free running native clock (CLKN) 2006 to synchronizethe estimated clock (CLKE) 2009 with the clock of the master. However,the paging sequence can fail during coexistent cellular transmission bythe communication device 100.

For example, when the communication device 100 is operating as a BTmaster it is possible that the slot used to transmit the page message atthe predicted frequency at which the slave is listening occurs during anLTE-TX subframe period. The page message may then fail because ofinterference between coexisting BT and LTE transmissions. Even if the BTtransmission is successful, it is possible that reception of the pageresponse will be unsuccessful due to an LTE transmission. To avoid thissituation, the page message at predicted frequency f(k) should beshifted such that it is transmitted, and the page response is received,without interference by an LTE transmission. The communication interface103 (FIG. 16) finds a slot pattern for transmitting the page message atthe predicted frequency f(k) and receiving the page response based atleast in part upon the LTE transmit and receive pattern of the LTEcommunication schedule. By comparing the schedule TX and RX pattern to aperiod of pattern periodicity with the BT slots, the communicationinterface 103 can identify a pattern of consecutive BT TX slot, BT RXslot, and BT TX slot that avoids an LTE-TX period or falls within anallowed BT RX period. The index of the identified TX-RX-TX slot patternmay be used to determine an align slot. With reference to FIG. 20, theCLKE 2009 is adjusted by adding the clock offset 2003, which includesthe estimated clock offset associated with the master clock plus theestimated TX/RX alignment adjustment of (8−slot alignment)*4, to CLKN2006. In general, the CLKN 2006 provides two ticks per slot (i.e., aperiod of 0.3125 ms), so shifting from one TX slot to the next TX slotcorresponds to 4 ticks of the CLKN 2006. The clock that is used formaster page response generation is also changed from using a frozenclock to using the frozen clock minus the estimated TX/RX alignmentadjustment of (8−align slot)*4 ticks.

Consider the example of FIGS. 21A and 21B where the communication device100 is operating as a BT master and a BT client 503 is operating as aslave listening on channel index 14. The BT interface 112 transmits asequence of the paging messages 2103 during the odd TX slots 2106. Inthe paging sequence 2103 of FIG. 21A, the page message 2109 at thepredicted frequency f(k) is transmitted at channel index 14 (x=600).However, even though page message 2109 may be transmitted to the slavedevice 503 during the allowed TX period 2112, the BT interface 112 mayfail to receive the page response because of coexisting LTEtransmissions. However, by adjusting the master clock of thecommunication device 100 by the estimated TX/RX alignment adjustment,the TX-RX-TX pattern may be aligned with the allowed RX period 2115. Asshown in FIG. 21B, by adjusting the master clock by −8 ticks, the pagemessage 2109 at the predicted frequency f(k) is transmitted at x=400.This brings the page response 2118 received in the next RX slot 2121within the allowed RX period 2115, which allows successful paging. TheFHS packet may then be transmitted during the allowed RX period 2115 toavoid possible LTE transmissions.

It should be noted that LTE time division duplex (TDD) configuration hasa bias towards an LTE-RX with respect to 5 ms periodicity. In the sevenTDD frame configurations of TABLE 1, the first and sixth subframes arealways downlink or DL (LTE-RX) as they carry secondary synchronizationssignals (SSS) signals. The second subframe is always special or S andthe seventh subframe is either special or downlink (LTE-RX). Even if theworst special subframe configuration with respect to uplink or UL(LTE-TX) subframes is considered, which has 0.167 ms for uplink pilottime slot (UpPTS), there is 1.833 ms for downlink (LTE-RX) for every 5ms. If the communication device 100 allows with WLAN and/or BTtransmissions even when LTE is receiving either by use of filters ortransmit power control on the WLAN and/or BT side, the LTE TDD frameconfiguration bias for scheduling the WLAN and/or BT traffic using the1.833 ms out of every 5 ms.

TABLE 1 config 0 DL S UL UL UL DL S UL UL UL config 1 DL S UL UL DL DL SUL UL DL config 2 DL S UL DL DL DL S UL DL DL config 3 DL S UL UL UL DLDL DL DL DL config 4 DL S UL UL DL DL DL DL DL DL config 5 DL S UL DL DLDL DL DL DL DL config 6 DL S UL UL UL DL S UL UL DL

In general, a standardized scheme for simultaneous transmission and/orreception by two transceivers based upon factors such as the filter onthe board, the frequencies of operation, etc. They are referred to ashybrid modes, an example of which is given in TABLE 2. An adaptivehybrid scheme may be used where the hybrid mode is dynamically selectedbased on the current operating conditions of the communication device100 (FIG. 24).

TABLE 2 WLAN-G/BT WLAN-G/BT TX RX Mode Comment LTE TX ✓ ✓ Hybrid0 Fullsimultaneous LTE RX ✓ ✓ operation LTE TX ✓ X Hybrid1 No WLAN-G/BT LTE RX✓ ✓ RX with LTE TX LTE TX ✓ ✓ Hybrid2 No WLAN-G/BT LTE RX X ✓ TX withLTE RX LTE TX ✓ X Hybrid3 Pure TDM (Only LTE RX X ✓ TX-TX and RX-RX) LTETX ✓ X Hybrid4 Same as Hybrid3 LTE RX X ✓ but TX of ACK/ Null datapacket is allowed during LTE DL period but not during PDCCH.

In the case of the communication device 100 operating as a BTLE master,the BTLE communications may experience severe interference fromcoexisting LTE transmissions during uplink and may affect LTE receptionduring downlink when the BT interface 112 (FIG. 16) is transmitting. Theeffects can be reduced by allowing the BTLE master to receive duringLTE-RX and only transmit during LTE-TX. A BTLE master in hybrid1 modemay also transmit during LTE-RX. FIGS. 22A and 22B illustrate examplesof connection setups to schedule BTLE communications. The first packetsent in a connection state by the BTLE master determines the anchorpoint for the first connection event, and therefore the timings of allfuture connection events in that connection. The anchor point can bescheduled so that master transmissions coincide with LTE-TX or LTE-FREEif the master is collocated with LTE and coincides with LTE-RX,LTE-RX/FREE, LTE-FREE or the non-uplink period of LTE-SPECIAL if theslave is collocated. A connection request (CONNECT_REQ) 2203 isinitiated such that the connection interval (connInterval) 2206 spans aninteger number of LTE frames. This may be achieved based upon acommunication schedule such as, e.g., the LTE TDD frame configurationschedule or a predictor map.

The communication interface 103 (FIG. 16) can determine a size(transmitWindowSize) 2212 of a transmit window 2215 and a transmitwindow offset (transmitWindowOffset) 2218. The connInterval 2206 can bechosen so that its size is a multiple of LTE frames. ThetransmitWindowOffset 2218 and transmitWindowSize 2212 may be adaptivelycalculated based at least in part upon the communication schedule. TheconnInterval 2206 may be adaptively aligned with LTE frame. As shown inFIG. 22A, the connInterval 2206 for the BTLE TX-RX-TX operations 2209may occur after 1.25 ms plus a delay interval (t) 2221 where the delayinterval is transmitWindowOffset 2218≦t≦transmitWindowOffset2218+transmitWindowSize 2212. In some cases, the transmitWindowOffset2218 may be set to zero (0) as illustrated in FIG. 22B. The secondconnection event anchor point will be the connInterval 2206 after thefirst connection event anchor point. The BTLE master can close theconnection event by setting a more data (MD) bit to zero (“0”) when theLTE-RX period is about to end. The allows the BTLE master to avoidinterference from subsequent LTE transmissions during the BLTE RXoperations even if the MD bit is set to one (“1”) by the slave.

Referring next to FIG. 23, shown is a flowchart that provides an exampleof coordination of coexisting BT and cellular communications inaccordance with various embodiments of the present disclosure. It isunderstood that the flowchart of FIG. 23 provides merely an example ofthe many different arrangements that may be employed for coexisting BTand cellular communications as described herein. As an alternative, theflowchart of FIG. 23 may be viewed as depicting an example of steps of amethod implemented in the communication device 100 (FIG. 16) accordingto one or more embodiments.

Beginning with 2303, a shift associated with a BT receive-transmit(RX-TX) transaction is determined by a communication device 100supporting coexisting BT and cellular communications based at least inpart upon a schedule for the cellular communications. The shift avoidsconcurrent BT RX with cellular TX and concurrent BT TX with cellular RXof the communication device 100. At least a portion of the BT RX-TXtransaction is shifted in 2306 based upon the determined shift. In someembodiments, the TeSCO interval corresponding to the BT RX-TXtransaction may be shifted by the determined shift to avoid concurrentBT RX with cellular TX and concurrent BT TX with cellular RX. In otherembodiments, a TX portion of the BT RX-TX transaction may be shifted bythe determined shift to coordinate reception of the TX portion with a TXsubframe period of the cellular communications without shifting a RXportion of the BT RX-TX transaction or a RX portion of the BT RX-TXtransaction may be shifted by the determined shift to coordinatereception of the RX portion with a RX subframe period of the cellularcommunications without shifting a TX portion of the BT RX-TXtransaction.

Referring to FIG. 24, shown is an example of a networked environment2400 including a communication device 100 with coexisting Wi-Fi,Bluetooth, and/or cellular communications. In the example of FIG. 24,the communication device 100 may be providing wireless access pointservices as a SoftAP 115 (FIG. 4) to one or more Wi-Fi clients 2403operating as a station (STA) or may be acting as a STA 118 (FIG. 8)communicatively coupled to a Wi-Fi client 2403 that is an AP through aWLAN 2406. One or more other Wi-Fi clients 2403 may also becommunicatively coupled to the AP through WLAN 2406. The communicationdevice 100 is also communicatively coupled to a cellular base station2409 via cellular network 2412. The cellular network 2412 may correspondto, e.g., an LTE or WiMAX network. Acting as a SoftAP allows thecommunication device 100 to facilitate tethering the one or more STAsthrough the cellular connection to access resources provided by throughthe cellular network 2412 and base station 2409. In the example of FIG.24, the communication device 100 is also communicatively coupled to oneor more BT client(s) 2415 via a personal area network (PAN) 2418 such asa piconet.

Coordination of the coexisting Wi-Fi (or WLAN), Bluetooth (BT), and/orcellular communications may be handled by the connection interface 103.A scheduler 2421 may be used to evaluate the coexisting communicationrequests. Cellular traffic (e.g., LTE) is given the maximum priority ofthe three coexisting communications. BT synchronous and isochronoustraffic is next in priority after LTE traffic. BT requests are placed bythe scheduler 2421 for evaluation. The LTE transmit and receive pattern(or access pattern) of the LTE communication schedule may be used forplacing an access request by the scheduler 2421. WLAN accesses are alsocoordinated with the LTE transmit and receive pattern of the LTEcommunication schedule.

Since the BT synchronous connection renders steady state traffic, thereis a dependency on the LTE TDD steady state access pattern based atleast in part upon the LTE configuration (see, e.g., TABLE 1). Becausefitting in the eSCO pattern with the LTE access pattern is different,eSCO is handled separately from ACL links. With the communication device100 operating as a BT master, the freedom of choosing the eSCO patternsis available. At the start of BT connection establishment, the followinginput and output parameters are determined for a supported eSCOconnection. Input parameters include, e.g., a LTE configuration, adiscontinuous reception (DRX) pattern, a semi persistent scheduling(SPS) pattern, and/or LTE frame synchronization information. Outputparameters include, e.g., TeSCO, DeSCO, and WeSCO values (standarddefined), BT shift (or frame alignment offset), packet type, RX payloadbytes/packet, and/or TX payload bytes/packet. LTE TDD configurationshave a DL/UL (or LTE-RX/LTE-TX) pattern duration of 10 or 5 ms. Asdiscussed with respect to FIG. 16, a BT TX/RX pattern will have aduration of the TeSCO interval in case of an eSCO connection. For LTEschedules, the BT eSCO combined pattern will repeat after a patternperiodicity. BT shift is the duration in time between the first LTE TDDframe start and the first BT TeSCO interval. The packet type may be usedto introduce a shift (or gap) between the TX and RX portions of a BTTX-RX transaction as discussed above. The output parameters may be usedto determine the BT access pattern which will have the duration of thepattern periodicity. Other periodic patterns that should be consideredare BLE connections and WLAN beacon transmissions.

Referring next to FIG. 25, shown is a flowchart that provides an exampleof coordination of coexisting WLAN, BT, and cellular communications bythe scheduler 2421 in accordance with various embodiments of the presentdisclosure. It is understood that the flowchart of FIG. 25 providesmerely an example of the many different arrangements that may beemployed for coexisting WLAN, BT and cellular communications asdescribed herein. As an alternative, the flowchart of FIG. 25 may beviewed as depicting an example of steps of a method implemented in thecommunication device 100 (FIG. 24) according to one or more embodiments.

Beginning with 2503, BT slots that are allowed to TX and/or RX aredetermined by the scheduler 2421. The LTE transmit and receive pattern(or access pattern) of the LTE communication schedule may be obtainedfrom the cellular interface 109 by the communication interface 103 andused by the scheduler 2421 to determine which BT slots are available forTX and/or RX based at least in part upon the access pattern. BTsynchronous connection parameters are then determined in 2506 todetermine the slot use. For example, TeSCO, DeSCO, and WeSCO values,packet type, RX payload size, and/or TX payload size may be determinedto avoid interference with the used slots as previously discussed. OtherBT parameters such as, e.g., a BT shift of the TeSCO intervals and/or aBT clock synchronization shift may also be determined. Thedeterminations may be based upon factors such as, e.g., BT connectionrequirements including TX throughput, RX throughput, maximum latency,and/or packet types supported by the slave and master. Existing reservedslots and/or hybrid modes supported by the communication device 100 mayalso be considered. The factors may be obtained from the BT interface112 (FIG. 24) and/or through negotiation with a slave. Based upon thedetermined synchronous connection parameters, BT eSCO requests may begenerated in 2509.

BTLE slots that are allowed to TX and/or RX may then be determined bythe scheduler 2421 in 2512 based at least in part upon, e.g., the LTEtransmit and receive pattern (or access pattern) and the BT slots beingused. The BTLE slots and related parameters are then determined for usein 2515. The determination may be based upon factors such as, e.g., BTLEconnections (and/or connection requirements) and/or hybrid modessupported by the communication device 100. BTLE connections can beanchored to free slots in pattern periodicity time interval. Theconnection interval (e.g., connInterval 2206 of FIGS. 22A and 22B) incase of BTLE can be a multiple of the pattern periodicity.TransmitWindowOffset and transmitWindowSize (e.g., 2218 and 2212 ofFIGS. 22A and 22B) should be selected such that the master poll packetfalls in the anchor point. Based upon the determined parameters, BTLErequests may be generated in 2518.

The WLAN beacon interval may be determined in 2521 based upon factorssuch as, e.g., WLAN beacon information and/or hybrid modes supported bythe communication device 100. For the WLAN beacon, an extrasynchronization between WLAN and BT may be used. When both WLAN and BTare active, WLAN indicates the beacon periodicity. Based upon theindicated beacon periodicity, a slot for WLAN is determined and anindication to WLAN is provided in 2524. This indication avoids a chanceof periodic overlap between a BT eSCO slot (or a BTLE slot) and the WLANbeacon. If there is no synchronous connection in BT, then thedetermination and indication may be bypassed and the WLAN interface 106can decide on the time by denying a grant in the case of a BT requestfor a time slot. In other implementations, the WLAN beacon time is notsynchronized but a history is maintained of how many beacons are lost.If the number of losses exceeds a predefined limit, then BT eSCO isdenied access, which can result in packet loss.

The remaining slots that are allowed to TX and/or RX may be allotted forBT ACL packets. In 2527, the BT packet type is determined for theconnection. ACL requests needs to be handled as and when it is required.Based upon the application parameters, a packet type and payload size isselected. The BT asynchronous connection parameters can include, e.g.,TX throughput, RX throughput, maximum latency, supported modes and/orhybrid modes supported by the communication device 100. This should beto meet the needed throughput while minimizing the air time. Forexample, the throughput that can be supported by each packet typesupported by the existing TX and/or RX slots can be determined, and theslot with the minimum air time may be chosen. Before generating ACLrequests in 2530, the LTE-TX and LTE-RX pattern (or access pattern) isrechecked to determine any modifications based upon the current DRXpattern available through, e.g., common ECI hardware. This may provideadditional TX and/or RX opportunities.

The eSCO request(s) 2509, BTLE request(s) 2518, WLAN beacon indication1514, and/or ACL request(s) 2530 may then be combined in 2533 and sentto the WLAN interface 106. The request to WLAN is placed (e.g., over anECI interface) a specified time period before the grant is needed and/orissued. The appropriate parameters corresponding to each request areincluded before the combined request is transmitted.

When there are no requests from BT, the WLAN channel is used based atleast in part upon the allowed TX and RX periods (or access pattern) ofthe LTE communication schedule (or predictor map). WLAN TX/RX controlcan achieved using protocols such as, e.g., RDG, CTS2self, null dataframes with power save modes, blockACK, and/or modified EDCA parametersas previously discussed. In the presence of BT and LTE, the request(s)from BT may be processed as indicated in FIG. 25. The BT request typemay also be indicated to determine the priority of the request. The WLANhas the authority to won or disown the request. When operating in aSoftAP 115 mode, the BSS should be setup in a channel of operation thatminimizes interference from the LTE communications. By settingappropriate EDCA parameters and broadcasting in the beacon, the SoftAP118 can maintain access of the WLAN channel. In this way, the SoftAP 118makes sure that the STAs will not transmit unless given a grant througha RDG. LTE-Free periods may be used to extend the grant period. Whenoperating in a STA 118 mode, the communication device 100 may remain ina sleep (or power save) mode and wake up at appropriate times toretrieve data. As described above, power save modes can be indicatedusing a null packet with PM bit set. In case of RDG support, there maybe control on the end of packet reception. In some embodiments, LTEuplink (UL) duration may be used for TX and LTE downlink (DL) durationwill be used for both TX and RX. In case there is no RDG support,transmission from an AP can extend over the UL duration due to excessamount of data or delayed response of AP. This can cause retransmissionsand throughput loss can occur.

FIGS. 26A through 26F show examples of coordination between variouscoexisting communications. Referring to FIGS. 26A and 26B, shown is anexample with an LTE configuration of config 1 (TABLE 1) in a hybrid1mode where BT is allowed to transmit at all times (allowed TX period2603 from LTE) and the BT RX is aligned with the LTE-RX (allowed RXperiods 2606 from LTE). The illustrated output of the WLAN eSCOconnection is based upon BT connection parameters of a TX throughput of64 kbps, a RX throughput of 64 kbps, and maximum latency of 8 (slots).The eSCO RX packets 2609 are distributed in the RX slots 2612 thatcorrespond to the allowed RX period 2606. The eSCO TX packets 2615 aredistributed in the TX slots 2618. The connection parameters to make thispossible may be determined by the scheduler 2421 to be TeSCO=6 (slots)(or 3.75 ms), DeSCO=0, WeSCO=1, TX payload bytes/packet=30 bytes, RXpayload bytes/packet=30 bytes, TX packet type=EV3, RX packet type=EV3,and BT shift (between LTE frame start and BT TeSCO interval start)=0.625ms.

Generally, the eSCO connection will not be alone. For example, in thecase of a hands free profile, an ACL channel can be used to control theBT head set parameter(s) such as, e.g., volume. This ACL control channelrequires very low throughput. FIG. 26B shows the positioning of ACL TXpackets 2621 and ACL RX packets 2624 on top of the eSCO connection. Themaximum throughput possible in this case is 18 kbps with an ACL packettype of DM1 in TX and RX direction. Even though FIG. 26B shows themaximum ACL packets 2621 and 2624 that can be accommodated, in actualpractice they may not be occupied or utilized. Or it may be possible tohave additional packets that can be accommodated based on the currentDRX pattern. Hence before forming requests for ACL packets, thescheduler 2421 reexamines the dynamic access patterns that are recentlycommunicated by the cellular interface 109.

Referring to FIG. 26C, shown is an example where the ACL throughput isasymmetric and in the order of supporting eSCO and an advanced audiodistribution profile (A2DP). In the example of FIG. 26C, the connectionparameters are TeSCO=6 (slots) (or 3.75 ms), DeSCO=4, WeSCO=2, TXpayload bytes/packet=30 bytes, RX payload bytes/packet=30 bytes, TXpacket type=EV3, RX packet type=EV3, BT shift (between LTE frame startand BT TeSCO interval start)=0.625 ms, ACL TX packet type=DH5 (maxpayload) and ACL RX packet type=DM1 (max payload). The maximumthroughput possible for the eSCO connection is 64 kbps in the TX and RXdirections and for the ACL connection is 361 kbps in the TX directionwith the different packet type and 18 kbps in the RX direction. FIG. 26Dshows another example of scheduling where a BTLE connection has beenincorporated including a BTLE RX packet 2527 and a BTLE TX packet 2530.The anchor points (connection interval) are fixed at a periodicity of amultiple of the pattern periodicity.

Referring next to FIGS. 26E and 26F, shown are examples of BT schedulingwith LTE semi persistent scheduling (SPS). For a particular application,the presence of a DRX pattern or SPS relaxes the situation slightly. Inthe example of FIG. 26E, operation is in a hybrid1 mode (TDM with DRXpattern). Shown is the BT scheduling (ACL TX packets 2621 and ACL RXpackets 2624) with SPS for voice once in 20 ms. It can be seen that theeSCO patterns of eSCO RX packets 2609 and eSCO TX packets 2615 are moreregular.

The maximum throughput possible for the eSCO connection is 64 kbps inthe TX and RX directions and for the ACL connection is 341 kbps in theTX direction and 50 kbps in the RX direction. In the example of FIG.26F, operation is in a hybrid3 mode (TDM with DRX pattern). The maximumthroughput possible for the eSCO connection is 64 kbps in the TX and RXdirections with EV3 packets and for the ACL connection is 292 kbps withDH3 packets in the TX direction and 27 kbps with DM1 packets in the RXdirection. The pattern periodicity will be the least common multiple(LCM) of the SPS period and the BE eSCO periodicity.

In case of SPS, the retransmission may also happen in an asynchronousmanner. When retransmission will occur, scheduling returns to the basicscheduling based on the TDD configuration. For BT, this can be done byre configuring the eSCO connections. Once the retransmission hascompleted, the scheduler 2421 may then switch back to the SPS basedscheduling. In this mode, a complicated scheduler is not needed and onlyBT needs to keep track of the LTE allowed slots. If a slot is notallowed, then it is almost guaranteed that next slot is allowed. In thatcase, simply hold the TX/RX for the next retransmission slot.

Referring to FIG. 27, shown is an example of coexisting BT and LTEcommunications. In FIG. 27, BT frequency hopping is carried out over afrequency range 2703 below the operating frequency band 2706 of the LTEcommunications. BT frequency hops 2709 that are in a predefined band2712 that is nearest to the LTE frequency band 2706 will operate inhybrid3 mode which is complete TDM, which means that only TX-TX andRX-RX combinations are allowed to coexist. If the BT communications fallin the next band 2715 away from the LTE frequency band 2706, thenoperation in a hybrid1 mode occurs, which means that BT transmissionsare allowed without regard to the LTE access state. The transitionboundary between band 2712 and band 2715 may depend upon the filtersthat are being utilized by the cellular interface 109 (FIG. 24). If theBT communications are at a frequency that is sufficiently far from theLTE frequency band 2706 (e.g., in band 2718), then a hybrid0 mode ofoperation may be used, where both the cellular interface 109 and the BTinterface 112 will operate independently. The information that may beused to decide the transition between hybrid modes of operation mayinclude frequency break points if they are continuous, bit mapscorresponding to each hopping point if they are discontinuous, and/orpredefined BT channels. The hybrid mode patterns may be determined basedupon SNR degradation, jamming effects, VCO coupling and/or VCO pullingissues, and/or intermodulation issues due to simultaneous operations(TX-RX, RX-TX) of the transceivers. The adaptive hybrid scheme may beimplemented as part of the scheduler 2421 or another part of thecommunication interface 103 (FIG. 24).

With reference to FIG. 28, shown is a schematic block diagram of thecommunication device 100 in accordance with various embodiments of thepresent disclosure. The communication device 100 includes at least oneprocessor circuit, for example, having a processor 2803 and a memory2806, both of which are coupled to a local interface 2809. Thecommunication device 100 may include one or more cellular interface(s)109, one or more WLAN interface(s) 106, and/or one or more BTinterface(s) 112, all of which may be coupled to the local interface2809. The WLAN interface(s) 106, comprise processing circuitry forsupporting Wi-Fi communications such as, e.g., IEEE 802.11 a/b/g/n orother wireless communication protocols. The cellular interface(s) 109comprise processing circuitry for supporting cellular communicationssuch as, e.g., LTE, WiMAX, WCDMA, HSDPA, or other wireless communicationprotocols. The BT interface(s) 112 comprise processing circuitry forsupporting Bluetooth communications such as, e.g., BT, BTLE, or otherwireless communication protocols.

In various embodiments, the processing circuitry is implemented as atleast a portion of a microprocessor. The processing circuitry may beimplemented using one or more circuits, one or more microprocessors,application specific integrated circuits, dedicated hardware, digitalsignal processors, microcomputers, central processing units, fieldprogrammable gate arrays, programmable logic devices, state machines, orany combination thereof. In yet other embodiments, the processingcircuitry may include one or more software modules executable within oneor more processing circuits. The processing circuitry may furtherinclude memory configured to store instructions and/or code that causesthe processing circuitry to execute data communication functions. Insome cases, portions of the WLAN interface(s) 106, cellular interface(s)109, and/or BT interface(s) 112 may be implemented by processor 2803 vialocal interface 2809. The local interface 2809 may comprise, forexample, a data bus with an accompanying address/control bus or otherbus structure as can be appreciated.

Stored in the memory 2806 are both data and several components that areexecutable by the processor 2803. In particular, stored in the memory2806 and executable by the processor 2803 may be a SoftAP 115, a STA118, a communication interface 103, a scheduler 2421, and potentiallyother applications and device interfaces. In some implementations, thecommunication interface 103 may include the scheduler 2421. In addition,an operating system may be stored in the memory 2806 and executable bythe processor 2803. In some cases, the processor 2803 and memory 2806may be integrated as a system-on-a-chip.

It is understood that there may be other applications that are stored inthe memory 2806 and are executable by the processor 2803 as can beappreciated. Where any component discussed herein is implemented in theform of software, any one of a number of programming languages may beemployed such as, for example, C, C++, C#, Objective C, Java®,JavaScript®, Perl, PHP, Visual Basics, Python, Ruby, Delphi®, Flash®, orother programming languages.

A number of software components are stored in the memory 2806 and areexecutable by the processor 2803. In this respect, the term “executable”means a program file that is in a form that can ultimately be run by theprocessor 2803. Examples of executable programs may be, for example, acompiled program that can be translated into machine code in a formatthat can be loaded into a random access portion of the memory 2806 andrun by the processor 2803, source code that may be expressed in properformat such as object code that is capable of being loaded into a randomaccess portion of the memory 2806 and executed by the processor 2803, orsource code that may be interpreted by another executable program togenerate instructions in a random access portion of the memory 2806 tobe executed by the processor 2803, etc. An executable program may bestored in any portion or component of the memory 2806 including, forexample, random access memory (RAM), read-only memory (ROM), hard drive,solid-state drive, USB flash drive, memory card, optical disc such ascompact disc (CD) or digital versatile disc (DVD), floppy disk, magnetictape, or other memory components.

The memory 2806 is defined herein as including both volatile andnonvolatile memory and data storage components. Volatile components arethose that do not retain data values upon loss of power. Nonvolatilecomponents are those that retain data upon a loss of power. Thus, thememory 2806 may comprise, for example, random access memory (RAM),read-only memory (ROM), hard disk drives, solid-state drives, USB flashdrives, memory cards accessed via a memory card reader, floppy disksaccessed via an associated floppy disk drive, optical discs accessed viaan optical disc drive, magnetic tapes accessed via an appropriate tapedrive, and/or other memory components, or a combination of any two ormore of these memory components. In addition, the RAM may comprise, forexample, static random access memory (SRAM), dynamic random accessmemory (DRAM), or magnetic random access memory (MRAM) and other suchdevices. The ROM may comprise, for example, a programmable read-onlymemory (PROM), an erasable programmable read-only memory (EPROM), anelectrically erasable programmable read-only memory (EEPROM), or otherlike memory device.

Also, the processor 2803 may represent multiple processors 2803 and thememory 2806 may represent multiple memories 2806 that operate inparallel processing circuits, respectively. In such a case, the localinterface 2809 may be an appropriate network that facilitatescommunication between any two of the multiple processors 2803, betweenany processor 2803 and any of the memories 2806, or between any two ofthe memories 2806, etc. The local interface 2809 may comprise additionalsystems designed to coordinate this communication, including, forexample, performing load balancing. The processor 2803 may be ofelectrical or of some other available construction.

Although the SoftAP 115, STA 118, communication interface 103, scheduler2421, and other various systems described herein may be embodied insoftware or code executed by general purpose hardware, as an alternativethe same may also be embodied in dedicated hardware or a combination ofsoftware/general purpose hardware and dedicated hardware. If embodied indedicated hardware, each can be implemented as a circuit or statemachine that employs any one of or a combination of a number oftechnologies. These technologies may include, but are not limited to,discrete logic circuits having logic gates for implementing variouslogic functions upon an application of one or more data signals,application specific integrated circuits having appropriate logic gates,or other components, etc. Such technologies are generally well known bythose skilled in the art and, consequently, are not described in detailherein.

The flowcharts of FIGS. 15A, 15B. 23 and 25 show the functionality andoperation of an implementation of portions of the communicationinterface 103 and/or scheduler 2421 and logic implemented by the WLANinterface(s) 106, cellular interface(s) 109, and/or BT interface(s) 112.If embodied in software, each block may represent a module, segment, orportion of code that comprises program instructions to implement thespecified logical function(s). The program instructions may be embodiedin the form of source code that comprises human-readable statementswritten in a programming language or machine code that comprisesnumerical instructions recognizable by a suitable execution system suchas a processor 2803 in a computer system or other system. The machinecode may be converted from the source code, etc. If embodied inhardware, each block may represent a circuit or a number ofinterconnected circuits to implement the specified logical function(s).

Although the flowcharts of FIGS. 15A, 15B, 23 and 25 show a specificorder of execution, it is understood that the order of execution maydiffer from that which is depicted. For example, the order of executionof two or more blocks may be scrambled relative to the order shown.Also, two or more blocks shown in succession in FIGS. 15A, 15B, 23 and25 may be executed concurrently or with partial concurrence. Further, insome embodiments, one or more of the blocks shown in FIGS. 15A, 15B, 23and 25 may be skipped or omitted. In addition, any number of counters,state variables, warning semaphores, or messages might be added to thelogical flow described herein, for purposes of enhanced utility,accounting, performance measurement, or providing troubleshooting aids,etc. It is understood that all such variations are within the scope ofthe present disclosure.

Also, any logic or application described herein, including thecommunication interface 103, scheduler 2421, WLAN interface(s) 106,cellular interface(s) 109, and/or BT interface(s) 112 that comprisessoftware or code can be embodied in any non-transitory computer-readablemedium for use by or in connection with an instruction execution systemsuch as, for example, a processor 2803 in a computer system or othersystem. In this sense, the logic may comprise, for example, statementsincluding instructions and declarations that can be fetched from thecomputer-readable medium and executed by the instruction executionsystem. In the context of the present disclosure, a “computer-readablemedium” can be any medium that can contain, store, or maintain the logicor application described herein for use by or in connection with theinstruction execution system.

The computer-readable medium can comprise any one of many physical mediasuch as, for example, magnetic, optical, or semiconductor media. Morespecific examples of a suitable computer-readable medium would include,but are not limited to, magnetic tapes, magnetic floppy diskettes,magnetic hard drives, memory cards, solid-state drives, USB flashdrives, or optical discs. Also, the computer-readable medium may be arandom access memory (RAM) including, for example, static random accessmemory (SRAM) and dynamic random access memory (DRAM), or magneticrandom access memory (MRAM). In addition, the computer-readable mediummay be a read-only memory (ROM), a programmable read-only memory (PROM),an erasable programmable read-only memory (EPROM), an electricallyerasable programmable read-only memory (EEPROM), or other type of memorydevice.

It should be emphasized that the above-described embodiments of thepresent disclosure are merely possible examples of implementations setforth for a clear understanding of the principles of the disclosure.Many variations and modifications may be made to the above-describedembodiment(s) without departing substantially from the spirit andprinciples of the disclosure. All such modifications and variations areintended to be included herein within the scope of this disclosure andprotected by the following claims.

It should be noted that ratios, concentrations, amounts, and othernumerical data may be expressed herein in a range format. It is to beunderstood that such a range format is used for convenience and brevity,and thus, should be interpreted in a flexible manner to include not onlythe numerical values explicitly recited as the limits of the range, butalso to include all the individual numerical values or sub-rangesencompassed within that range as if each numerical value and sub-rangeis explicitly recited. To illustrate, a concentration range of “about0.1% to about 5%” should be interpreted to include not only theexplicitly recited concentration of about 0.1 wt % to about 5 wt %, butalso include individual concentrations (e.g., 1%, 2%, 3%, and 4%) andthe sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within theindicated range. The term “about” can include traditional roundingaccording to significant figures of numerical values. In addition, thephrase “about ‘x’ to ‘y’” includes “about ‘x’ to about ‘y’”.

What is claimed is:
 1. A method, comprising: determining, by acommunication device supporting coexisting Bluetooth (BT) and cellularcommunications, a shift associated with a BT receive-transmit (RX-TX)transaction to avoid a concurrent BT RX with a cellular TX and aconcurrent BT TX with a cellular RX, the shift based at least in partupon a schedule for the cellular communications; and shifting at least aportion of the BT RX-TX transaction based upon the determined shift. 2.The method of claim 1, further comprising shifting a TeSCO intervalcorresponding to the BT RX-TX transaction by the determined shift toavoid the concurrent BT RX with the cellular TX and the concurrent BT TXwith the cellular RX.
 3. The method of claim 1, further comprisingshifting one or both of a TX and an RX portion of the BT RX-TXtransaction by the determined shift to allow for BT communicationsscheduling.
 4. The method of claim 1, further comprising shifting a TXportion of the BT RX-TX transaction by the determined shift tocoordinate reception of the TX portion with a TX subframe period of thecellular communications and leaving an RX portion of the BT RX-TXtransaction unchanged.
 5. The method of claim 1, further comprisingshifting an RX portion of the BT RX-TX transaction by the determinedshift to coordinate reception of the RX portion with a RX subframeperiod of the cellular communications and leaving a TX portion of the BTRX-TX transaction unchanged.
 6. The method of claim 5, furthercomprising adjusting a payload of a respective TX packet of the TXportion of the BT RX-TX transaction for an air time of one slot.
 7. Themethod of claim 5, further comprising using a packet type, for the TXportion of the BT RX-TX transaction, having a packet duration of anumber of slots to affect a desired shift of the RX portion of the BTRX-TX transaction.
 8. The method of claim 7, further comprising usingthe packet type and the packet duration to affect the desired shift ofthe RX portion of the BT RX-TX transaction based at least in part upon aschedule of a long term evolution (LTE) communication.
 9. The method ofclaim 1, further comprising determining a slot pattern for transmittinga BT page message and receiving a page response based at least in partupon a schedule of a long term evolution (LTE) communication.
 10. Themethod of claim 1, further comprising determining a size of a BTtransmit window and a BT transmit window offset adaptively based atleast in part upon a schedule of a long term evolution (LTE)communication.
 11. A communication device supporting coexistingBluetooth (BT) and cellular communications, the communication devicecomprising: a communication interface configured to determine a shiftassociated with a BT receive-transmit (RX-TX) transaction to avoid aconcurrent BT RX with a cellular TX and a concurrent BT TX with acellular RX, the shift based at least in part upon a schedule for thecellular communications; and a BT interface configured to shift at leasta portion of the BT RX-TX transaction based upon the determined shift.12. The communication device of claim 11, wherein the BT interface isconfigured to shift a TeSCO interval corresponding to the BT RX-TXtransaction by the determined shift to avoid the concurrent BT RX withthe cellular TX and the concurrent BT TX with the cellular RX.
 13. Thecommunication device of claim 11, wherein the BT interface is configuredto shift one or both of a TX and an RX portion of the BT RX-TXtransaction by the determined shift to allow for BT communicationsscheduling.
 14. The communication device of claim 11, wherein the BTinterface is configured to shift a TX portion of the BT RX-TXtransaction by the determined shift to coordinate reception of the TXportion with a TX subframe period of the cellular communications and toleave an RX portion of the BT RX-TX transaction unchanged.
 15. Thecommunication device of claim 11, wherein the BT interface is configuredto shift an RX portion of the BT RX-TX transaction by the determinedshift to coordinate reception of the RX portion with a RX subframeperiod of the cellular communications and to leave a TX portion of theBT RX-TX transaction unchanged.
 16. The communication device of claim15, wherein the BT interface is configured to use a packet type, for theTX portion of the BT RX-TX transaction, having a packet duration of anumber of slots to affect a desired shift of the RX portion of the BTRX-TX transaction.
 17. The communication device of claim 16, wherein theBT interface is configured to adjust a payload of a respective TX packetof the TX portion of the BT RX-TX transaction for an air time of oneslot.
 18. The communication device of claim 16, wherein the BT interfaceis configured to use the packet type and the packet duration to affectthe desired shift of the RX portion of the BT RX-TX transaction based atleast in part upon a schedule of a long term evolution (LTE)communication obtained by the communication interface.
 19. Thecommunication device of claim 11, wherein the BT interface is configuredto: determine a slot pattern for transmitting a BT page message and toreceive a page response based at least in part upon a schedule of a longterm evolution (LTE) communication obtained by the communicationinterface; and determine a size of BT transmit window and a BT transmitwindow offset adaptively based at least in part upon a schedule of along term evolution (LTE) communication.
 20. A communication systemcomprising: a communication device coupled via a cellular network to acellular base station; a number of Bluetooth (BT) clients coupled via apersonal area network (PAN) to the communication device, wherein thecommunication device is configured to support coexisting BT and cellularcommunications and comprises: a communication interface configured todetermine a shift associated with a BT receive-transmit (RX-TX)transaction to avoid a concurrent BT RX with a cellular TX and aconcurrent BT TX with a cellular RX, the shift being based at least inpart upon a schedule for the cellular communications obtained from acellular interface; and a BT interface configured to shift at least aportion of the BT RX-TX transaction based upon the determined shift.